1. Field
The present invention relates to an energy storage device having a collector plate, and, more particularly, to an energy storage device and a method of manufacturing thereof, wherein a collector plate is interposed between an electrode and a conductive terminal, so to provide an improved distribution of the electrical charge from the electrode to the base and reduced manufacturing costs.
2. Related Art
Energy storage devices generally comprise a plurality of electrodes that are in ionic contact with an electrolyte, and that provide a negative charge to a negative terminal and a positive charge to a positive terminal.
One type of energy storage device is a capacitor, wherein each electrode is formed by an activated carbon mixture spread over a metallic sheet serving as a collector for the electrode charge. Each electrode/collector sheet combination is separated from the adjacent electrode/collector sheet combination by a dielectric material, for example, by a paper sheet.
In one type of capacitor, the electrode/collector sheet/dielectric material/electrode/collector sheet assembly is would together to form a spiral composition, known in the industry as a “jellyroll.” A suitable container of tubular shape houses the jellyroll and the electrolyte, the container having a negative electric terminal at one end and a positive electric terminal at the opposite end that are electrically isolated one from the other.
The operation of the capacitor is made possible by causing the collector sheet supporting the negatively charged electrode to be connected to the negative terminal, and the collector sheet supporting the positively charged electrode to be connected to the positive terminal. Such a collector sheet/terminal connection is generated by having the collector sheet carrying the negative charge to extend out of one edge of the jellyroll to come in contact with the negative terminal, and by having the collector sheet carrying the positive charge to extend from the opposite edge of the jellyroll to come in contact with the positive terminal. The collector sheet/terminal connection may be insured by means of a laser welding process, during which a collector sheet is laser-welded in predetermined points to the respective container base carrying the terminal. This laser welding process, however, limits the number of connection points between the collector sheet and the base, and is time-consuming to perform. Further, the laser welding process may cause perforations in the container base, generating leaks of the electrolyte that must be prevented or corrected by sealing the base with a suitable compound, such as an epoxy compound.
Therefore, there is a need for an energy storage system having larger contact area between the collector sheet and the base carrying the electric terminal.
There is a further need for an energy storage device with reduced manufacturing times in comparison with the prior art.
There is a still further need for an energy storage device that does not need preventive or corrective care to avoid electrolyte leaks caused by the laser welding process.